Question

Solve and check the equations
(a) 1 - 4x = -11
(b) y + 3/2 = 5

Class - IV

Linear Equations

Answer 1

SOLUTION :

(a) 1 - 4x = -11

⇒ -4x + 1 - 1 = -11 - 1  [ Adding -1 to both sides ]

⇒ -4x = -12

⇒ $\frac{-4x}{ \bf{4} }$ = $\frac{-12}{ \bf{4} }$

⇒ -x = -3

⇒ x = 3     [ As minus(-) divided by minus(-) is plus(+) ]

∴ x = 3 is the solution of the given equation [ 1 - 4x = -11 ]

VERIFICATION

LHS = 1 - 4x

       = 1 - 4 × 3     [ Put the value of x = 3 ]

       = 1 - 12

       = -11 = RHS

∴ Hence LHS = RHS (verified)

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(b) y + 3/2 = 5

⇒ y + $\frac{3}{2}$ - $\frac{ \bf{3} }{ \bf{2} }$ = 5 - $\frac{ \bf{3} }{ \bf{2} }$    [ Adding - $\frac{ \bf{3} }{ \bf{2} }$ to both sides ]

⇒ y = $\frac{ 10 - 3 }{2 }$    [ Taking 2 as LCM in RHS ]

⇒ y = $\frac{ \bf{7} }{ \bf{2} }$

∴ y = $\frac{ \bf{7} }{ \bf{2} }$ is the solution is the solution of the given equation [ y + 3/2 = 5  ]

VERIFICATION

LHS = y + 3/2

       =  $\frac{ \bf{7} }{ \bf{2} }$ +  $\frac{ \bf{3} }{ \bf{2} }$    [ Put the value of y =  $\frac{ \bf{7} }{ \bf{2} }$ ]

       =  $\frac{ \bf{10} }{ \bf{2} }$

       = 5 = RHS

∴ Hence LHS = RHS (verified)

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Answer 2

Answer:

(a) -4x = -11 - 1

(1 goes to RHS and sign changes)

-4x=-12

(both - signs get cut )

4x=12

x=12/4

x=3

(b)y = 5 - 3/2

(3/2 goes to RHS and sign changes) LCM =2

y= 5*2/2 - 3/2

y=7/2

Step-by-step explanation: